Combination electric heater



Aug. 21, 1923. `1,465,355

E. G. EBERHARDT v COMBINATION ELECTRIC HEATER Filed July 22, 1922 2 Sheets-Sheet l 'Aug 21, 1.923.

E. G. EBERHARDT coMBINA'rIoN ELECTRIC HEATER Filed July 22, 1922 l2 Vsmaets--sheet 2 Y To all whom it may concern:

`Patented Aug. 2l, 1923.

EMAN'UEI. G. EBERIIARDT, 0E RACINE, wIsC'oNs'IN.

COMBINATION ELECTRIC HEATER.

Application led July 22,

` Be it known that I, EMANUEL G. EBER- HARDT, a citizen of the United dStates,"a nd resident of Racine,`in thev6 county of Racine and State 'of Wisconsin, have invented certain new and useful Improvements in Combination Electric Heaters; and I do hereby declare'that the following is. a full, clear, and exact description thereof.

This invention relates to electric heaters, and is particularly directed to a combination heater.

which is equipped with meansto allow rality o comprise a series of resistance wires' 5, of.

Objects of this invention are to provide a combination electric device which may be used. as .a toaster, a hot plate, and a convection type of heater; to provide an electric heater which may be quickly changed from one type to another; and to provide a heater of rugged and sturdy formation.

Further` objects are to provide `a heater or the expansion and contraction ofthe heating element; which is permit the use Aof a single die the upper and lower portions; and which fully 'protects the heating elements in whatever capacity4 the heater may bev used.

An embodiment of the invention is shown in the accompanying drawings, in

which Figure 1 is-a plan view, with parts broken away, showing the device as it appears when used as a convection type of heater.

Figure 2.,is a side elevation of the structure shown in Figure 1.

Figure `3 is an end elevation of the structure shown in Figure 2. 1

Figure2.

he fdevice'comprises. a base portion, or frame, which has a top lhaving an open central ortion and suspported by 'a pluleg's 2. `The heating element may any desired material such as will offer a re1- atively high electrical resista-nce and rel'sist oxidation and fusion. These 'wires 3 are stretched between refractory end memi any variation Yin the bers, 4or plates, 4 'which are yieldingly pressedapart to maintain the'wires 'taut and to prevent sagging, thereby compensatlength of the wires. he' yieldingmounting 4for 'the members 4 is attained by securing a pluralityv of pairs of aligned, spaced rods 5 lthe refractory end plates so constructed as to in forming Fgure 1 is a section on the. line 4?-4 of andl 6 to these members, by means of thenuts 8, and posi- 1922. seriai'No. 576,840.

duced diameter to provide a shouldered portion.v It may bev found desirable to provide a pair of washers 11 and 1 2 upon the reduced portions and upon opposite sidesor` 4.- One of the washers may bear against the shouldered portison of the rod and the other against the nut The end platesl may be formed of any desired refractory, insulating material,a combination of asbestos and Portland cement has been found satisfactory. These members are preferably provided with a plurality of relatively shallow slits extending downwardly from their upper edges. The resistance vwires, or heating wires, are passed through these slits and loop around the portions of the end plates between such slits. In this manner, the wires are located provided with a grid 13 which is plurality of thin metal straps which may be either freely interlaced, or may be. ositively joined atA their crossing points. f he ends'of 'the grid -/tioning a compression spring 7 between the I are s ecuredto a bead 14 of the bottom memy ber, and rest upon the top edges of the refA fractory members 4.

The ends of the wires 3 are secured to terminals 15 to which the attaching cable may4 be 'either permanently or detachably joined, such cable. "thereafter leading outwardly through the opening 16.

A convenient manner of supporting the 'entire heating unit is to provide. angle irons,

or transverse members, 21 which are'secured within the base portion. These members sup` port the reduced extensions 10 of the rods 5. and 6 and allow such rods to freely adjust'l themselves,k The`heating unit is held in place by the grid 13 whichbears upon the end members 4. j

, The device as thusrfar described, is admirablyadapted for use als a hot Aplate or i being t protecting plate 17 spaced a material distance below the heating element, to prevent the direct radiation of heat to the support u on which the utoaster may be laced.

is plate further enhances the e ect of the device as it upwardly reflects the normally wasted heat rays. It is to be noted thatthe plate 17 is spaced a slight distance below the lower edge of the top or body por tion 1 of the bottom member to allow free circulationA of air.

When it is' desired to-convert this type of'device into' convection heater, a rectangular 'drum 18 is slipped 'over the bead or upwardly projecting flange 14 of the botfom member, and is secured in place by means of spring .clips 19 carried by the bottom member and cooperating with suitably shaped portions of the drum 18. 'The rum is surmounted by a topP 20 identical with the top l of the bottom member,-in fact, both members 1 and 20 are `formed by the same die: The central upper portion of the top member is open and mayor may not be provided with an open work grid.

When the heater is used with the top member in place, the convection currents of air are greatly augmented. The air freely I' stantially uni has *en provided which may passes-between the lower 1 of the bottom and the plate 17 and, after bein heated by the wiresl 3, passes u wardglythrou h the drum 18rat a relative rapid rate. IF metallic drum 18 and top 20 aid in distributing the heat as they provide, in effect, radiating surfaces.

It is found that the tensioning means provided for the wires 3, aids in the assembly of the heatinv element, asA it assures a suborm tension of the wires, and thereby relieves the assembler of the necessity of exactly securing the desired tension as he places each wire 1n position.

It will be seen that a combination heater be readily andqickly changed from one type of heater to anothg. It will further be 'seen that veffective means have been provided for preedge of the member venting `sagging of the heating wires, and

f lI c aim: l A

1. electric heater comprising a frame,

for maintaining the correct tension.

t will further be seen that a heater has en provided which mayv very readily and cheaply manufactured,l and which is of sturd and rugged formation. v

ycomprising a base, t is also to belnoted that the b v'111g a drum adapted to CODSIIL members carried by said rods, a tube hous-` ing said resilient means andl a portion of said rods, andi resistance elements strung between said members, whereby any ,variatin in length of said elements will be compensated for by said resilient means;

3. An electric heater comprising a frame, rods slidably 'carried thereby, resilient means tending to force said rods apart, refractory members carried by said rods, resistance elements strung between said members, and a supporting grid'resting upon said members.

1. An electric heater comprising a frame, aligned spaced rods slidably carried thereby, resilient means interposed between the ends of said rods, a tube surroundin said resilient means and a portion of saidg. rods, refractory members secured to the outer ends of said rods, a heating element stretched between said members, 'y and' a protecting grid carried by said frame and resting upon said members., f

5. A combination electric heating' device a heating element carried y lsaid base and located above its lower portion, a protecting openwork a distance above said heatin adapted to support articles to a removable drum .adapted to to said base to surround and wardly from said heating element to increase convection crrents' of air.

6. An electric heater comprising a base portion \including a top member havin anopen central portion, a to portion in udcietachably fit the base ortion and Surmounted b a top member identical with that of the base rtion, an openwork grid positioned across tbz open port1on of the top member for the base portion, and heating elements carried by the base and positioned belo,w the grid.

In testimony that I I have hereunto set my-hand at Racine, in the .county of A'Racine and State of Wise ement 'and heated,.and be attached extend up EMANUEL Ler. EBERHARDT.

rid spaced claim the foregoing 

